The present invention relates generally to electronic musical instruments or tone generators which allow a performance assisting function, such as a so-called key depression guide function, to be provided for a desired performance part. More particularly, the present invention relates to an apparatus and method which can properly associate or relate appropriate performance data (i.e., track-by-track performance data trains) with a plurality of performance parts, to thereby set an appropriate correspondence between the performance tracks and the performance parts.
In recent years, electronic musical instruments have been known extensively which have additional functions of not only executing an automatic performance in accordance with previously-provided automatic performance data but also providing a visual performance assistance or guide to sequentially indicate keys to be depressed in accordance with progression of a performance (hereinafter called a "key depression guide function") so that even a beginner can perform a desired music piece. Typical examples of the key depression guide function employed in piano-type electronic musical instruments include a function of sequentially indicating keys to be depressed by sequentially turning on/off light-emitting diodes (LEDs) disposed in corresponding relation to the keyboard keys, and a function of indicating key operation start timing and key operation end timing of the keys (i.e., key depression timing and key release timing) using a liquid crystal display screen provided on the electronic musical instrument.
The electronic musical instruments of the above-mentioned type are normally designed to selectively activate the key depression guide function for either one or both of a right-hand performance part (corresponding to a melody performance) and a left-hand performance part (corresponding to a chord performance). In performance practice with the key depression guide function activated, each performance part selected as a subject of the key depression guide function is set to a "mute" condition, i.e., a condition where only visual indication of keys to be depressed is given via the key depression guide function with no tone generated at all by the automatic performance function for that selected performance part; in this case, however, tones are generated via the automatic performance function for every other performance part not selected as a subject of the key depression guide function as well as for every accompaniment part. In this way, a user or human player is allowed to practice a manual performance of the desired performance part while listening to the actually-generated tones of the other parts.
Automatic performance data used for the above-mentioned functions generally comprise event data indicative of tone generation and tone deadening events (turning on/off of tones) and timing data indicative of respective tone generating timing of the individual events, which are pre-recorded for each of a plurality of performance parts in a predetermined tone progression order. To each of the event data is added track number data indicating which of the performance parts that event data belongs to. The conventional piano-style musical instruments are also arranged to properly activate the aforementioned key depression guide function by relating the track numbers with the performance parts in such a way that the event data with a track number "1", for example, is regarded as the data of the right-hand performance part (such relationship or correspondence of the track numbers with the performance parts will hereinafter be called "track assignment"). However, to date, there has been no unified standard for such correspondence between the track numbers and the performance parts; the standard differs variously among various manufactures of musical instruments. As a consequence, there would occur the problem that even the same event data with a particular track number is interpreted as data of the right-hand performance part in the musical instrument of one manufacturer but as data of the left-hand performance part in the musical instrument of another manufacturer, and vice versa.
To avoid such a problem, more sophisticated piano-style musical instruments are constructed to set appropriate correspondence between the tracks and the performance parts, by prestoring information representing such a track-to-part correspondence (this information will hereinafter be called a "track assignment table") of each individual manufacturer. Thus, each time instructions for reading out new automatic performance data are given, these musical instruments operate to set a track-to-part correspondence by making reference to one of the prestored track assign tables in accordance with which of the manufactures the new automatic performance data pertains to (i.e., which of the manufactures created that new automatic performance data).
In some cases, however, even a single musical instrument manufacture is using two or more different sets of track assignment settings. Therefore, the prestored track assignment table can not always permit appropriate setting of track assignment for all the automatic performance data, in which case there would arise a need for the user or human player to manually make new track assignment settings. Conventionally, the thus-manually make new track assignment settings are never stored for subsequent use, and thus, whenever the user has selected another music piece to be automatically performed, the manually-made track assignment settings are cleared to be replaced by any one of the prestored sets of track assignment settings. Because the track assignment table also contains "substitute" track assignment state information that is applicable to any other manufacturer than those pre-registered in the table, it has been conventional for a certain track assignment setting operation to be carried out on every new music piece selected. Accordingly, the manual track assignment setting operation must be carried out upon readout of each automatic performance data set for which no appropriate track assignment information has not been pre-recorded in the track assignment table. Consequently, even when automatic performance data, all recorded in a same recording format, are to be read out in succession, a new track assignment setting operation must be made by the user unless the track assignment table includes track assignment information corresponding to that particular recording format, which would require a very cumbersome and time-consuming operation by the user.